I was merely checking to see if you were using a custom made kernel. As you are not, you can safely ignore that. The latest Realtek drivers from the URL in the guide includes $(uname -r) which executes then returns/stores the results (2.4.22-1.2115.nptl in your case) into the KERNELRELEASE variable, saving you the extra step of editing the Makefile. Had you been running a custom made kernel, **** would've hit the fan (although it would be a simple fix as well).